Fix logging
Fix logging

Use a Queue which enqueues lines from proc.stdout in a separate thread.
Review URL: https://codereview.appspot.com/6765045

git-svn-id: 32fc27f4dcfb6c0385cd9719852b95fe6680452d@6074 2bbb7eff-a529-9590-31e7-b0007b416f81

Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot